Differential effects of anesthetics on in vivo skeletal muscle contractile function in the mouse

Christopher R. Ingalls, Gordon L. Warren, Dawn A. Lowe, Daniel B. Boorstein, R. B. Armstrong

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The purpose of this study was to evaluate the effects of four anesthetic regimens on in vivo contractile function of mouse ankle dorsiflexor muscles. The torque-frequency and torque-velocity relationships were determined for the following anesthetics: fentanyl-droperidol and diazepam (F-d/d); ketamine and xylazine (K/x); pentobarbital sodium (Ps); and methoxyflurane (Mf). Mf, Ps, and F-d/d regimens resulted in comparable contractile responses at low doses, whereas K/x produced a relative depression in isometric contractile function as shown by a decrease in the torque-time integral at the 300-Hz stimulation frequency (-13.9%; P < 0.050. Moreover, K/x caused a shift to the left in the torque-frequency curve as indicated by increases in torque-time integrals at 25 and 50 Hz. Both Ps and F-d/d regimens exhibited dose- dependent effects during the isovelocity contractions. Ps significantly reduced work (-28.7%) and average power (-28.9%) at 800°/s at the high dose. In contrast, F-d/d anesthesia resulted in increases in peak torque (1620%) and work (15-18%) output at all eccentric contraction velocities at the high dose, whereas average power was increased only at 800 (17%) and -1,000°/s (17%). In conclusion, commonly used anesthetic regimens can affect the contractile response in vivo; K/x and Ps yield smaller torque outputs, whereas Mf and F-d/d consistently produce larger contractile responses. Mf and F-d/d are recommended for use in studying skeletal muscle function in mice in vivo.

Original languageEnglish (US)
Pages (from-to)332-340
Number of pages9
JournalJournal of applied physiology
Issue number1
StatePublished - Jan 1996


  • average power
  • concentric
  • eccentric
  • isometric
  • peak torque
  • work


Dive into the research topics of 'Differential effects of anesthetics on in vivo skeletal muscle contractile function in the mouse'. Together they form a unique fingerprint.

Cite this